Mobile communication devices, such as cellular telephones (generally referred to herein as “mobile devices”) have become an integral electronic accessory in many people's lives. In addition to the ability to send and receive voice calls, mobile devices have become popular devices from which to conduct data communications. Many are using their mobile devices as wireless data modems connected to other computing devices (e.g., a laptop computer) to send and receive email and connect to the Internet to browse sites on the worldwide web. Since mobile devices conduct data communications over a cellular communication network whose coverage is rapidly expanding, mobile devices provide users with the ability to conduct wireless data communications over a greater geographic range than most other current technologies, such as WiFi.
Computing devices (e.g., a laptop computer) can be connected to mobile devices via a tethered cable (i.e., USB, IEEE 1394, etc) or via a wireless connection (i.e., Bluetooth, IEEE 802.11, Zigbee, etc.). When so configured, the mobile device acts as a wireless modem coupling the computing device to a cellular communications network which can provide access to the Internet. Using the mobile device as a wireless modem allows users to conduct data communications over the broad range of cellular communications network while utilizing the larger keyboard, display, memory, processor, and battery of a terminal computing device
In computer networking, a “MTU” (maximum transmission unit) refers to the size (in bytes) of the largest packet or frame that a given layer of a communication protocol can pass onwards. MTU parameters usually appear in association with a communications interface (e.g., NIC, serial port, etc.). The MTU may be fixed by standards (as is the case with Ethernet) or decided at connect time (as is usually the case with point-to-point serial links). A higher MTU brings higher bandwidth efficiency. However, large packets can block a slow interface for some time, thereby increasing the lag for further packets. For example, a 1500 byte packet, the largest allowed by Ethernet at the network layer (and hence most of the Internet), would tie up a 14.4 kB modem for about one second. Regardless of whether users conduct data communications directly on a mobile device or over a computing device connected to the mobile device as a wireless modem, it is important to synchronize either the mobile device alone or the mobile device and computing device with the network to insure that the MTU set so as to optimize the data communication link.